Internal gear finishing machine



Sept. 30, 1941. J. D. RovlcK 2,257,195

INTERNAL GEAR FINISHING MACHINE Original Filed Nov. 18, 1935 5 Sheets-Sheet 1 INVENTOR ATTORNEYS Sept. 30, 1941. J. D. ROVICK INTERNAL GEAR FINISHING MACHINE 5 Shets-Sheer. 2

Original Filed Nov. 18, 1935 Sept. 30, 1941. RQVlCK 2,257,195

INTERNAL GEAR FINISHING MACHINE Original Filed Nov. 18, 1955 5 Sheets-Sheet s a a \1 J 2 N BY I I! A ATTORNEY-S Sept. 3 1941. J. D. RovlcK INTERNAL GEAR FINISHING MACHINE Original Filed Nov. 18, 1935 5' Sheets-Sheet 4 INVENTORI Jiznfi EOVZC% ATTORNEYS Sept. 30, 1941. RQVlCK 2,257,195

INTERNAL GEAR FINISHING MACHINE Original Filed Nov. 18, 1935 5 Sheets-Shae 5 NVENTOI H ATTORNEY-S v Patented Sept. 30, 1941 manner. can rmrsnmamcnma John D. Bovlck, Munoie, Ind., assignor to Michian Tool Company, Detroit, Mich, a eorporation of Delaware Continuation of application SerialNo. li,41 2, no-

vember 18, 1935.

1939, Serial No. 269,739

8 Claims.

The present invention relates to gear finishing machines and particularly to machines for lapping, burnishing andshaving internal gears, and is a continuation of application Serial No. 50,- 4l2, filed jointly by the present applicant and Joseph R. Richer on November 18, 1935, and assigned to the same assignee as the present application.

Objects of the present invention include the provision of an improved machine for lapping, burnishing and shaving internal gears; an improved machine for supporting a finishing tool in variably mating relation to the teeth of an internal gear to finish the latter; to provide a machine embodying means to rotatably support an internal gear and a finishing tool in variably mating relation to each other; to provide a machine in which the finishing tool and gear axes are disposed at an angle to each other, introducing a lateral component or motion between the gear teeth and tool teeth; to provide a machine in which the tool is given a component of motion radially of the gear to cause the tool to move from a position of slight mating contact with the gear teeth to, at least, a position of full mating contact with such teeth; to provide a machine in which the direction of movement and rotation of the tool and gear are reversible; to provide a machine as above stated in which in moving from a positionof slight mating contact to a position of full mating contact with the gear, the tool moves in an arcuate path, and to provide such a machine characterized in that the tool and the work will be translated relative to each other in such relation as to distribute the finishing action over the entire tooth faces of the work and to also distribute the wear over the tooth faces of the tool.

Further objects of the present invention include the provision of an improved adjustable head or cradle for rotatably supporting an internal gear in cooperative relation to a. finishing tool: to provide such a cradle which is pivotally adjustable to vary the angle between the axis 01! the gear and the axis of a cooperating finishing tool; to provide such a cradle embodying conveniently actuable means for pivoting the cradle; and to provide' a cradle embodying means to impose a brakingdoad on the gear.

Further objects of the present invention include the provision of a supporting structure for a finishing tool, em dy ng means to effect a simultaneous rotation and bodily movement of th tool with respectto an internal gear being fin- This application April 24,

structure, in which the bodily movement of tool occurs in an arcuate path and in which, in moving in the arcuate path, the tool moves from a position of slight mating contact with the teeth 01' the gear being finished, to at least a position of full mating contact; to provide a tool support as above stated, embodying a tool shaft rotatably supported within an eccentric sleeve, and to provide a tool support as last stated, embodying a universal joint connection between the tool shafts and an external source of power.

With the above and other objects in view, which appear in the following description and in the appended claims, an illustrative and preferred embodiment of the present invention is shown in the accompanying drawings, throughout the several views of which corresponding reference characters are used to designate corresponding parts, and in which:

Fig. 1 is a view in ndlelevation of" the preferred embodiment of the machine;

Fig. 2 is a fragmentary view illustrating the automatic reversing and stop control mechanism shown generally in Fig. l;

Fig. 3 is a view' taken along the line 3-3 of Fig. 2;

Fig. Us a top plan view of the structure shown in Fig. 1;

Fig. 5 is a view in front elevation, with certain of the parts broken away, of certain of the structure shown in Figs. 1 and 4; I

Fig. 6 is a view in vertical central section taken along the line 66 of Fig. 1;

Fig. '1 is a fragmentary view in horizontal section taken along the line |'I of Fig. 5;

Fig. 8 is a partial view in vertical section, taken along the line 8-8 of Fig. '7;

Fig. 9 is aview in horizontal section, taken along the line 9- 9 of Fig. 6; and

Fig. 10 is a fragmentary view of a modified cradle The copending application of Joseph H. Drader and John 'D, Rovick, the present applicant, Serial No. 37,671, filed August 24, 1935, and assigned to the same assignee as the present application, discloses and claims certain of the broader aspects of lapping, burnishing and shaving "0! internal v gears by rolling a finishing tool within an internal gear and simultaneously moving the finishing tool in an arcuate path so'that during the rolling, the tool moves from a position of slight ished'thereby; to provide such a tool supporting 5 mating contact with the gear teeth to at least a position of full mating contact therewith, and preferably to a position beyond suchfliull mating contact relation to a secondiposition c1 slight discloses a tool I26 from an initial mating contact; The just identified application also discloses the principle of disposing the axes of the gear and of the tool at an angle to each lands being dressed to finishing edges, such for example as disclosed in the copending application ofiW. F. Dalzen, Serial No. 554,192, filed July, 1931, and Serial No. 588,635, filed January .25.

1932, and of Alex w. Simowski, Serial No.'50,381,

filed November 18, 1935, now Patent No. 2,119,298, all of which are assigned to the same assignee as tlie present application. A further application of the present applicant, John D. Rovick, Serial 0. 30,792, filed July 11, 1935, and assigned to the s e assignee as the present application,

xkclaims a similar method of finishing internal gears by running them with a finishing tool, and an improved form of tool in which the tool teeth are crowned at their intermediate portions to overcome any tendency towards the formation of crowns in the teeth of the gear during the hing operation.

The prese t invention is directed principally to an improved construction of machine for practicing the lapping, burnishing' and shaving method disclosed in the above identified Drader and Rovickapplications, and in theuse of which for shaving or combined burnishing and shaving, tools of the type disclosed and claimed inthe above identified Dalzen, Simowski, and Rovick applications are preferably used. p

Inthe form illustrated, the improved gear finishing machine of the present invention comprises generally a cradle 40 for rotatably supporting the internal gear 20 to be finished in cooperative relation to a finishing tool I20, and with the axis of the internal gear 20 at a selectively adjustable inclination to the axis 'of the finishing tool I20; and Supporting mechanism for the finishing tool I20, including the eccentrically mounted spindle I26, effective to cause it to roll with the gear, and also to move bodily with respect to the gear. The bodily movement occurs in an arcuate path by virtue of the eccentric spindle mounting, and as position of slight mating contact with the teeth of the gear 20 through a position of full mating contact with the gear teeth and to a final position of slight mating contact with the gear teeth. In'the course of this movement, a radial sliding movement occurs between the gear and tool teeth. Because of the inclination between the axes of the gear 26 and of the tool I20, the rolling together thereof introduces a lateral component of movement between the gear and tool teeth. The combined lateral and radial movements of the tool and gear teeth produce a finishing action which, in practice, is found to accurately finish the gear teeth to a desired tooth form, and also to make uniform the wear on the tool teeth, thus prolonging the life of the latter. 1

Gear supporting structure Considering first the construction of the supporting cradle 46 for the internal gear 26, and

referring particularly to Figs. 1, 4, 5, and 6, the

extending annular shoulder internal gear 20, which may be of either the spur or spiral type, is fitted within an adapter bush with the outer wall of gear 20. The upper edge of shoulder 24, as viewed in Figs. 5 and 6, is

. sloped so that, in assembly of the parts, the sloping face of the shoulder cams gear 20 and bushing 22 to positions of axial alignment with each other. Bushing 22 is also provided with an an- 1 nular shoulder 26 at the base thereof, upon which thelower edge of gear 20 rests.

Bushing 22 is also provided with an outer an nular shoulder 26, which forms a seat for one edggof the inner ring of a double bearing unit it. The other edge of the inner ring ofthe ball bearing unit 30 is engaged by a downwardly extending collar portion 32 of a ring 34. Ring 84 is removably bolted to the top of bushing 22 by the series of bolts 36. The outer ring of ball bearing unit 30 is secured between the inwardly 36 of the yoke or cradle 40 and a corresponding shoulder formed in a plate 42 which is removably secured to the base of yoke 46.

Ring 34 is provided with two downwardly extending tapped openings, which receive the correspondi'ngly threaded shanks 44 of a pair of adjustable locking devices 46. Each locking device 46 comprises a screw threaded rod 48, the lower end of which is disposed to be turned down into rigid engagement with the surface of the gear 20, to thereby positively retain it in correct position with respect to bushing 22. The rods 48 are threaded through pins 50 which in turn are pivotally mounted in the bifurcated portions 52 with which the shanks 44 are integrally formed.

With the assembly as thus far described, it will be understood that by loosening the locking devices 46, the screw threaded rods 48 may be rotated to horizontal positions and thereafter the bifurcated portions 52 also rotated upon their shanks 44, moving the locking devices 46 out of range of the gear 26. With the parts in this re:- lation, gear 20 may be removed through the upper end of the bushing 22, and a new gear inillustrated brings the plate 42, so that all the movement between them is through the ball'bearings 30.

The gear supporting structure thus far described is particularly suitable for use where the thickness of the tool teeth is correct for full mating capacity with the gear teeth. In this instance, throughout the movement between the gear and the tool, both sides of the gear teeth are engaged by the tool teeth and a positive drive between them is provided, both sides of the gear teeth being finished simultaneously.

For some shaving operations it is desirable to use tool teeth which are thinner than required for full matingwith the gear teeth, one side of the gear teeth being finished during one direction of movement of the gear and tool and the other side being finished during a reverse opera- In such instances, it is desirable to ima secured within and fOl rotationby an elongated I tubularshaft I23. In accordance with conven- 22' which may correspond to the previously described bushing 22. Bushing 22' is rotatably supported in yoke 43" which may correspond to the previously described yoke 43. A brake arm H is pivoted to yoke 40 and is provided with a shoe?" which engages the outer surface of bushing 22-;

Suitable mechanism to vary the braking load is illustrated as comprising the cam handle 43. 7

Continuing with the general construction,- the left hand and tapered shank 33 of yoke 43, as viewed in Figs. 4 and 5, is received within a correspondingly tapered boss 32, adjustably secured upon a bed plate 34 by the usual locking studs 33, and may be drawn inwardly thereof and secured in place by the locking stud 33. The right hand end of yoke 43, as viewed in Figs. 5 and 4, is formed to provide an upwardly extending arm 13, and a cylindrical trunnion 12, rotatably supported in a boss 13. Part of the surface of trunnion 12 is provided with inwardly cut threads which mate with a worm gear 14. Worm 14 is suitably supported inboss 13 upon :a shaft 15 and may be turned by an external adjusting nut tional practice, a rod I23 passes axially through shaft I23,"the upper threaded end thereof being threaded within the internally threaded lower end of chuck I24 and the lower end thereof bein; provided with a tightening nut I33. As will 13. A locking nut 13 is also threaded on shaft 13 and may be turned into locking engagement with the face 19 of boss 13 to lock'worm 14 in a selected rotative position. It will be understood that rotation of worm 14 by adjusting nut 13 effects a corresponding rotation of trunnion 12, which in turn determines the tilt of the axis of gear 23. A convenient measure of this axial angle with respect to the vertical is afforded by the sine bar arrangement comprising the pin 33 secured to the previously mentioned upwardly extending arm 13 and a corresponding pin 32 which is secured to the extension 34 which extends upwardly from boss 13. The relationship of these two pins is shown most clearly in Fig. 1 and it will be evident that the axial spacing between the two is a measure of the angle between the axis of gear 23 and a vertical axis. As described below, the axis of the finishing tool is vertically disposed so that pins 32 and 33 constitute a measure of the displacement angle between the axes of the gear and of the tool.

' be understood, b tightening nut I33, chuck I24 is securely drawn into and locked within'shaft 10.

I23, providing a rigid driving connection between shaft I23 and gear I23. A protective apron I21 is preferably fitted over the. upper end of chuck I24.

Shaft I23 is eccentrically supported and freely rotatable within a sleeve I32 for reasons described in detail below, upon the combined radial and thrust ball bearing units I34 and I33. The outer rings of each of the ball bearing units I34 are secured between an annular shoulder formed in sleeve I32, and a corresponding shoulder formed in a collar I 33 which is fitted over the end of sleeve I32. The inner rings of each of the ball bearing units I34 are secured between the shoulders formed in shaft I23 and a spacing sleeve. I43 which fits over shaft I23.

The outerrings of the lower ball bearing units I33 are fitted into the lower end of the sleeve I32.

' The inner rings thereof. are fitted over shaft I23 and are secured between a spacing collar I42 which abuts the spacing sleeve I43 and a spacing collar I44, also fitted over shaft I23. Spacing collar I44 abuts a ring or bevel gear I43 which is keyed or otherwise secured to shaft I23 and provides a drive therefor. Gear I43, and consequently collar I44, bearing unit I33, collar I42 and sleeve I43 are maintained in position axially of shaft I23 by the spacing sleeve I43, an additional combined radial and thrust ball bearing unit I33 and the stop collar I52, which is threaded Preferably, and as illustrated, bed plate 34,

carrying with it the bosses 32 and 13 and consequently the assembly comprising yoke 43, is sidable bodily along the frame 33 of the machine, on ways 92 formed therein to accommodate the machine to gears of different sizes (Fig. 1). The adjustment may be effected by hand wheel 34, carried on a shaft 33 which also carries a worm 33 which mates with and correspondingly drives a lead screw I33. The relation between lead screw I33, frame 33 and bed plate 34 may be of any conventional type and the details '-thereof have been omitted from the drawings to simplify them.

Tool supporting structure upon the lower end of shaft I23.

Bevel gear I43 mates with and is driven by a corresponding bevel gear I33 which is non-rotatably but removably secured upon the inner end of a shaft I32 by the stud I34 and plate I33. Shaft I32 is rotatably journalled within a boss I33 through the combined radial and thrust ball bearing units I13, the inner rings of which are secured in position axially of shaft I32 by'the shoulder I12, the spacing sleeve I14 and the collar I13 which is interposed between gear I33 and a shoulder I13 formed in shaft I32. The outer rings of the ball bearing unit I13 abut the shoulders I33 formed in boss I33.

Boss I33 is formed integrally with the lower part I32 of a housing, which surrounds and is secured upon the lower end of sleeve I32 and shaft I23. The upper half I34 of the housing is rctatably fitted over a collar I33 formed at the lower end of sleeve I32, and which is concentric with the shaft I23. The lower half I32 of the housing is radially supported with respect to shaft I23 through the outer rings of the previously mentioned radial and thrust ball bearing units I53. Axial support for housing I32 is afforded by the plates I33 and I33. Plate I33 is secured upon the upper surface of the base of'housing I32. Plate I33 is fitted on the lower end of housing I32 abutting the lower edge of the outer ring of ball bearing unit I33 and also accommodates a suitable packing gland I32. I

As shown in greater detail in Figs. 7 and 8, the end of shaft I32 remote from the bevel gear I33 is splined to a sleeve 233 which is freely rotatable, but axially fixed, withina boss'23 2 formed intmraily with a housing designated generally of'shaft I02, shaf 204. The combined radial and thrust ball hearing units '200 are preferably provided between 202 and sleeve 200. the outer rings of which abut shoulders 200 inboss 202, and a plate 2l0 wardtbr'ustofsleevelfl and the parts carried thereby istaken by the previously mentioned cover plate I00, the outer annular shoulder 000 of which bears against the inner ring of the upper which is'fltted overthe outer end of boss 202. v5 ball bearlngunit 200. a

The inner rings of the ball bearing units 200 abut respectively a shoulder 2l2 formed-in sleeve 200,

and a spacing collar 2| 4 which is interposed'between a shoulder 2I0 on sleeve 200 and a bevel A worm wheel 002, tightly fitted or otherwise secured over the lower end of sleeve I02, to provide a drive therefor and secured in place thereon by a collar 004, mates with a worm 000/which is gear 220 which is removably secured upon the keyed to a shaft 000 by key 0l0.

inner end of sleeve 200 by the nut 222.

- The housing 204 is formed in two parts which are securedtogether by studs220 and'is freely rotatable upon trunnions 200. Trunnions 200 lar 202, which fits within corresponding circular openings formed in the bosses 204 which extend from and are formed integrally with the gear housing designated generally 200. Studs 200 Shaft as a suitably journaled in the machine frame 00, and also carries a worm wheel 0I2 whi W0 0 issecured upon a shaft 0I0, which also are each formed with anaxially concentric cob-.15 carries a relatively-large gear 0I0. Gear 0I0 is driven by a suitable external source of power illustrated as a motor 020, through belting 022, pulley 024, and a pinion 020, carriedon the same shaft as pulley 024 and disposed to mate with are preferably provided to non-'rotatably securezo gear 0".

trunnions 200 within the bosses 204.

The bevel gear 240, which drives the previously mentioned bevel gear 220through the intermediate bevel gear 242, is secured upon the inner With the drive just described, it will be evident I that rotation of motor 020 effects a corresponding rotation of worm wheel 002 and, consequently, of sleeve I02, the gearing relationship being such end of a short shaft 244, for rotation thereby, by that the independently driven tool I20 and the the stud 240 andplate 240. Shaft 244 is rotatably journalled in the boss 200 formed in housing200 within the radial and thrust ball bearing units 252. As will be evident, shaft 244 is secured in sears make a substantial number of revolutions.

during the time that sleeve I02 is making a'small fraction of a single revolution. The partial revolution of sleeve I02, through the eccentric mountplace axially of boss-200m the manner described mg of shaft I20. causes tool I20 to move bodily,

in connection with the other bevel gear 220 and sleeve 200. The intermediate gear 242 is carried upon a shaft 200 which is freely rotatable, but axially fixed, within the previously mentioned bosses 204 thro h the combined thrust ball be ring units 202.

A suitable drive for shaft 204, and consequently I4 I20 and gear I20, is illustrated as represented by the gear 210 which is secured upon the outer end of the shaft 244, and a co-v operating pinion 212, secured upon the outer end of an intermediate drive shaft 214.- Shaft 214 is rotatably mounted on the ball bearing units as within a housing 2|0 which may be formed integrally with or suitably secured to the main machine frame 00. Shaft 214 also carries at its inner end one or more drive pulleys 200, which are driven from a suitable external source, such as a motor 202 (Fig. 4) through belting 204.

A continuous drive from motor 202 is thus pro-, vided for tool I20 through the universal connection comprising gears 220, 240 and 242, the splined connection of shaft I02 to sleeve 200, and through the bevel gears I40.and I00. The last mentioned drive elements comprise what may be called a universal connection between motor 202 and tool I20, which is provided to absorb the previously mentioned bodily movement of tool I20 along the arcuate path with respect to gear 20.

with particular reference to the structure which provides the just mentioned bodily move-' ment of tool I20 in the arcuate path, and referring particularly to Figs. 1, 4, 0 and 6, the previously mentioned sleeve I02 within which shaft I26 is eccentrlcally mounted, is rotatably 8119- 5 ported within the main machine frame 00 upon the ball bearing units 200 and 202. The ball bearing units200 are secured between a shoulder formed in the frame 00 and a corresponding shoulder formed in the coverplate 204, which 70 may be secured to the frame 00 in any suitable manner., The lower ball bearing units 202 are secured between a second shoulder formed in the frame 00 and a cover plate 200, which also acradial and tain instances it may be desirable to provide a 40 working range within the arcuate path of tool I20,

and a loading position outside of such working range. Also the working range may vary, including a period of vel from slight mating to just past full ma or alternatively to a second position of mating, depending upon the type of tool being used, and also upon whether a brake is employed forthe gear.

Preferably, and as illustrated, mechanism is provided to automatically fix the limits of the working range of the bodily movements of tool I20, which responds to the movement of tool I20. Referring particularly to Figs. 1, 2, 3, 4, 5 and 6. a dished timing gear 000 is suitably supported on a shaft 002 iournaled in bosses 004, which may form a part of the machine frame 00, in mating relation to the previously described worm gear 000, so that it is driven thereby simultaneously and in accordance with the rotation of the worm wheel 002 and eccentric sleeve I02. At its outer end, the shaft 002 carries a timing wheel I00.

A pair of switch actuating lugs 000 and 040 are removably and adjustably secured adjacent the periphery of timing wheel 000 by the studs 042. The lugs 000 and 040 are each provided with oppositely turned flanges 044 and 040, respectively, thefian'ge 044 beingdlsposed to engage a dog 000 which is secured upon a shaft 000 and the flange 040 is disposed to engage a corresponding dog 002, also carried upon the shaft 000 in axially spaced relation to the dog 040. Shaft 000 also carries a switch actuating arm 004, the bifurcated left hand end of which, as viewed in Fig. 2, receives a pin 000 which is secured upon the operating bar of a circuit controlling switch indicommodates a packing gland m. The downcated enerally at ga men of do: us

mates with and is driven by'a worm 0I4.-

by lug as during counterclockwise rotation oi timing wheel "I as viewed in Fig. 2, rotates arm I in a clockwise direction irom the position shown in Fig. 2 to an opposite position. Similarq 1y, engagement oi dog I" during clockwise rotation of timing wheel I", rotates arm ill from iects a corresponding rotative movement oi the gear ii, and the bodily movement in the arcuate path. gradually brings the gear ill and tool Ill into correct center distance relation. In certain instances, the, finishing operation may be eiiected by limiting the bodily movement of tool III such second position to the position illustrated in I 2. m; will be understood. the actuation of switch I as described maybe utilized to eilect various stopping and reversing relationships oi either or both of motors 2H and 320. The'intermediate connections, as well as any supplementary manual connections have been omitted from the drawings to simplify them.

Operation as a whole Considering the operation of the machine as a whole, and as described in more detail above. a gear to be finished, may be inserted within the adapter bushing Hyassociated with cradle 40, by withdrawing the locking devices 4' and turning them out of the way. It will be understood that diilerent sizes of bushings 22 may be provided to accommodate gears of varying outside diameters. Upon insertion of a gear 20 within bushing 22, the locking devices 48 may be applied, positively securing the gear 20 within the yoke 40. As a further preliminary to placing the machine in operation, the angle of cradle or yoke 40 and, consequently, of gear 20. with respect to the tool I20 may be appropriately adjusted by turning the adjusting nut 16, the sine pins 8| and 82 being provided as previously described to measure the displacement angle.

As described in more detafl in theabove identified copending applications, where a spur type of tool is used to finish a spiral type 0! gear, the axis of the gear is displaced from that of the tool by an angle equal to the spiral angle oi the gear. Where a spiral type of tool is used to finish a spiral type of gear, the axis of the tool is displaced at an angle to the axis of the tool by an angle equal to the difference between the spiral angle of the tool and of the gear.

As a further preliminary operation, bed plate 64, carrying with it cradle 40 and gear 20, may be adjusted longitudinally of the machine, thus effecting a corresponding radial movement between gear 20 and tool I20, to accommodate the machine to gears of different inside diameters.

The above described preliminary adjustment produces a relation betweenthe gear 20 and the tool I20, such that the tool teeth are in condition of partial mating relation with the teeth of the gear 20. In instances where the teeth of the tool I20 have correct thickness for iull mating capacity with the gear Ill, and where no brake is employed in connection with the gear 10, the initial adjustment is preferably such that both faces of the gear and tool teeth are in engagement with each other, the center distance between the tool I20 and gear 20 being slightly in excess of the correct center distance. In other instances such, for example, as where .the teeth of the tool I20 are thinner than required for full mating capacity with the teeth of the gear 20, and where a brake is employed in connection with the gear 20, the initial ce'nter distance between the gear 20 and the tool lilmay be somewhat more in excess of the correct center distance than as just stated.

Upon starting of the rotative and bodily movements of tool I20, which preferably occur simultaneously, the rotative movement of the tool etbetween the above stated initial positionand a position just slightly past the correct center. In other instances, the finishing operation may be eiiected by continuing the bodily movement of the 1 III somewhat past the position of full ma relation to a second position of partial mating relation. In certain instances, also, a complete finishing operation may include only a single movement from partial mating position to full mating position. Alternatively, several suchcomplete movements may be utilized successively. Depending also, upon the type of tool, the teeth of the gear 20 may be finished one side at a time, one side being finished during one direction of movement of the tool I20 and the other side of the gear teeth being finished during the opposite direction of movement of the tool ill; or both faces of each tooth may be finished in a single operation. a

In each of the above instances, the slipping movement between the teeth of the gear 20 and of the tool I20, caused jointly by the crossed axes thereof, and by the bodily movement of the tool l2. with respect to the gear 20, produces a finished gearhaving teeth of accurate tooth form, the finishing action being extended uniformly over the entire tooth faces of the gear 20, and the wear being distributed over the entire tooth faces of the tool I20, thus prolonging the life of the latter.

Although specific embodiments of the present invention are described, it will be evident that various changes in the form, number and arrangement of parts may be made within the spirit and scope of the present invention.

What is claimed is: I

1. A gear finishing machine comprising in combination, means for supporting a tool for rotation in a predetermined plane, means for supporting a gear in engagement with the tool for rotation in a plane at an angle to the first mentioned 'plane so that the gear and tool are in crossed axes relation, means for rotating the tool to drive the gear, and means eflective during the driving of the tool to cause a bodily movement of the tool in a plane perpendicular to its axis along a path generally tangential to the gear whereby to move the gear and tool between positions of partial mating contact and full mating contact.

2. A gear finishing machine comprising in combination a cradle for supporting a gear for rotation in a predetermined plane, means including a bearing for supporting a tool in engagement with the gear for rotation in a plane at an angle to' the first mentioned plane so that the gear and tool are in crossed axes relation, means for rotating the tool so as to drive the gear, and eccentric means for supporting the tool bearing and actuable during the driving of the tool, to cause a bodily movement of the tool in a plane perpendicular to its axis so as to move the gear and tool between positions of partial mating contact and iull mating contact.

3. The method of finishing a gear member, utilizing a finishing tool member which includes supporting the gear member for rotation in a predetermined plane, supporting the tool member for rotation in a plane at an angle to the first 6 a 833ml ment of one ofthe members during the thereof and in the plane of said one member along a path generally tangential to the gear whereby .to move the, gear and,tool between positions of partial mating contact and full mating contact.

' 4.- A gear finishing machine comprising in combination, means for supporting a finishing tool member for rotation in a predetermined plane, means for supporting a gear member in engagement with the tool for rotation in a plane at an angle to the first mentioned plane so that 15 the axes of said tool and gear are in crossed axes relation, means for driving one of the members so as to drive the other, and means efiective during said driving to bodily move one of the members in the plane thereof along a path so having a substantial component tangentially of the other member whereby to introduce an axial translatory movement between the. tool andgear.

5. A gear finishing machine comprising in combination, means for supporting ,a finishing as tool member for rotation in a predetermined plane, means for supporting a gear member in engagement with the tool for rotation in a plane at an angle to the first mentioned plane so that the axes of .said tool and gear are in crossed so 'axes relation, means for driving-one of the memberssoas to drive the other, and means efiective during the driving to bodily move one of the members along a path having a substantial component tangentially oi the other member so 35 as to introduce an axial translatory movement. I between the tool and gear.

s. The memes or finishing a gear mem er,

' utilising a finishing tool member which includes supporting the gear member for rotationin a predetermined plane, supporting the tool member for rotation'in a plane at an angle to the first plane so that the axes of the gear and tool are in crossed axes relation, driving said gear and tool in rotation, and eilecting a bod-, ily movement 01' one of the members during the driving thereof and in the plane obsaidone member along a path having asubstantial component tangentially of the other member,

'1. A gear finishing machine comprising means for rotatably supporting a gear-like finishing tool, means for. rotatably supporting a gear to be finished said last mentioned supporting means serving the axes of the gear and tool inclined with respect topach other whereby to introduces. component of lateral slippage between the working surfaces of the teeth of the tool and gear when the same are run'in-meshing engagement, means I for rotating the gear and tool, and means for cheating a bodily move- :ment of said tool in a direction perpendicular to the axis'of the tool and alonga path generally tangential to the gearv being finished whereby to bring said tool from a position of partial mating contact to a podtion of full mating contact.

8. The method oi finishing a gear member which comprises meshingsaid gear member with J a gear-like tool with the axis of the tool inclined to the axis of the gear, rotatably driving said gear and tool in meshing engagement and bodily moving said tool relative to said gear along y a path tangential to said gear.

I JOHN D. 

